Boot CPU is assumed to be always present in QEMU code. So
until that assumptions are gone, deny removal request.
In another words, QEMU won't support boot CPU core hot-unplug.
Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
[dwg: Tweaked error message for clarity]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This reverts commit 5cbc64de25.
Now that we have stable cpu_index values for pseries-2.7 (and future)
machine types, we can now safely allow hotplug and unplug in any order.
Conflicts:
hw/ppc/spapr_cpu_core.c
Some conflicts on revert due to some small changes in the inserted
code since the original commit.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
It will enshure that cpu_index for a given cpu stays the same
regardless of the order cpus has been created/deleted and so
it would be possible to migrate QEMU instance with out of order
created CPU.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The goal of this patch is to have a stable core-id which does not depend
on any DT related semantics, which involve non-obvious computations on
modern PowerPC server cpus.
With this patch, the DT core id is computed on-demand as:
(core-id / smp_threads) * smt
where smt is the number of threads per core in the host.
This formula should be consolidated in a helper since it is needed in
several places.
Other uses for core-id includes: compute a stable cpu_index (which
allows random order hotplug/unplug without breaking migration) and
NUMA.
Signed-off-by: Greg Kurz <groug@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
If CPU core addition or removal is allowed in random order leading to
holes in the core id range (and hence in the cpu_index range), migration
can fail as migration with holes in cpu_index range isn't yet handled
correctly.
Prevent this situation by enforcing the addition in contiguous order
and removal in LIFO order so that we never end up with holes in
cpu_index range.
Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
If the host has 8 threads/core and the guest is started with:
-smp cores=1,threads=4,maxcpus=12
It is possible to crash QEMU by doing:
(qemu) device_add host-spapr-cpu-core,core-id=16,id=foo
(qemu) device_del foo
Segmentation fault
This happens because spapr_core_unplug() assumes cpu_dt_id == core_id.
As long as cpu_dt_id is derived from the non-table cpu_index, this is
only true when you plug cores with contiguous ids.
It is safer to be consistent: the DR connector was created with an
index that is immediately written to cc->core_id, and spapr_core_plug()
also relies on cc->core_id.
Let's use it also in spapr_core_unplug().
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Tracked down with an ugly, brittle and probably buggy Perl script.
Also move includes converted to <...> up so they get included before
ours where that's obviously okay.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Tested-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Richard Henderson <rth@twiddle.net>
During CPU core realization, we create all the thread objects and parent
them to the core object in a loop. However, the realization of thread
objects is done separately by walking the threads of a core using
object_child_foreach(). With this, there is no guarantee on the order
in which the child thread objects get realized. Since CPU device tree
properties are currently derived from the CPU thread object, we assume
thread0 of the core to be the representative thread of the core when
creating device tree properties for the core. If thread0 is not the
first thread that gets realized, then we would end up having an
incorrect dt_id for the core and this causes hotplug failures from
the guest.
Fix this by realizing each thread object by walking the core's thread
object list thereby ensuring that thread0 and other threads are always
realized in the correct order.
Future TODO: CPU DT nodes are per-core properties and we should
ideally base the creation of CPU DT nodes on core objects rather than
the thread objects.
Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This patch changes spapr_cpu_core_realize_child() to have a local error
pointer and use error_propagate() as it is supposed to be done.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
When a core is being realized, we create a child object for each thread
of the core.
The child is first initialized with object_initialize() which sets its ref
count to 1, and then added to the core with object_property_add_child()
which bumps the ref count to 2.
When the core gets released, object_unparent() decreases the ref count to 1,
and we g_free() the object: we hence loose the reference on an unfinalized
object. This is likely to cause random crashes.
Let's drop the extra reference as soon as we don't need it, after the
thread is added to the core.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Introduction of core based CPU hotplug for PowerPC sPAPR didn't
add support for 970MP and POWER8NVL based core types. Add support for
the same.
While we are here, add support for explicit specification of POWER5+_v2.1
core type.
Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The "ICP" is a different object than the "XICS". For historical reasons,
we have a number of places where we name a variable "icp" while it contains
a XICSState pointer. There *is* an ICPState structure too so this makes
the code really confusing.
This is a mechanical replacement of all those instances to use the name
"xics" instead. There should be no functional change.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[spapr_cpu_init has been moved to spapr_cpu_core.c, change there]
Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Introduction of core based CPU hotplug for PowerPC sPAPR didn't
add support for 970 and POWER5+ based core types. Add support for
the same.
Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This fixes a potential QEMU crash introduced by commit 3b54254966.
Signed-off-by: Greg Kurz <groug@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Remove the CPU core device by removing the underlying CPU thread devices.
Hot removal of CPU for sPAPR guests is achieved by sending the hot unplug
notification to the guest. Release the vCPU object after CPU hot unplug so
that vCPU fd can be parked and reused.
Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Set up device tree entries for the hotplugged CPU core and use the
exising RTAS event logging infrastructure to send CPU hotplug notification
to the guest.
Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Introduce sPAPRMachineClass.dr_cpu_enabled to indicate support for
CPU core hotplug. Initialize boot time CPUs as core deivces and prevent
topologies that result in partially filled cores. Both of these are done
only if CPU core hotplug is supported.
Note: An unrelated change in the call to xics_system_init() is done
in this patch as it makes sense to use the local variable smt introduced
in this patch instead of kvmppc_smt_threads() call here.
TODO: We derive sPAPR core type by looking at -cpu <model>. However
we don't take care of "compat=" feature yet for boot time as well
as hotplug CPUs.
Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Start consolidating CPU init related routines in spapr_cpu_core.c. As
part of this, move spapr_cpu_init() and its dependencies from spapr.c
to spapr_cpu_core.c
No functionality change in this patch.
Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
[dwg: Rename TIMEBASE_FREQ to SPAPR_TIMEBASE_FREQ, since it's now in a
public(ish) header]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Add sPAPR specific abastract CPU core device that is based on generic
CPU core device. Use this as base type to create sPAPR CPU specific core
devices.
TODO:
- Add core types for other remaining CPU types
- Handle CPU model alias correctly
Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Bharata B Rao